Method of treating textile mate



Patented Oct. 3 1, 1950 METHOD OF TREATING TEXTILE MATE- RIALS AND THE RESULTING PRODUCTS Richard Thomas, Bromborough, England, assignor to Lever Brothers Company, a corporation of Maine N Drawing.

Application April 10, 1946, Serial No, 661,068. In Great Britain April 12, 1945 Claims. I

This invention relates to the treatment of textile materials, such as yarns, fabrics or articles made therefrom, in order to impart thereto an apparent whiteness, and more particularly, to the treatment of white textile materials with a substantive fluorescent stilbene derivative which does not darken upon exposure to sunlight, air, or bleaching agents. It also relates to the resulting treated textiles.

It is well known that white textile materials with the lapse of time and particularly after repeated washings tend to lose their original brightness and white appearance and gradually acquire a yellow tint or similar off-white shade. To suppress or counteract this progressive deterioration in color it is customary practice in laundering operations to subject the washed material to a blueing treatment by means of a non-substantive blueing agent such as ultramarine which enhances the apparent whiteness of the materials. It is usual to give the washed material, after removal of the detergent liquid, a plurality of rinses in water and the blueing'agent is generally added to the last rinse.

It has been proposed to eliminate the yellowish or off-white tint of materials such as textile fabrics, paper and the like, by treating the materials during manufacture of subsequently by immersion or otherwise with a solution of a compound of the coumarin group, preferably betamethyl umbelliferone. While, however, betamethyl umbelliferone and other fluorescent compounds of the coumarin group are capable of achieving a whitening effect, this effect disappears when the treated fabrics are rinsed, washed, or otherwise treated in aqueous solutions, due to the non-substantive character of the coumarin type of compounds.

It has been proposed to treattextile materials, in order to impart colored fluorescence thereto when illuminated'by ultraviolet light, with relatively large amounts of a stilbene derivative, such as 4:4-dibenzoyldiaminostilbene- 2:2'-disulfonic acid, which is applied to the textile in an aqueous bath containing a large amount of salt, for instance, 20% of Glauber salt. There has been no proposal of treating a textile with an aqueous solution having a very small concentration of a stilbene derivative, especially in the absence .of a salt. The amount of the stilbene derivative in these particular materials which are intended to be decorative or clearly visible in ultraviolet light must be such as to impart a brilliant colored fluorescence when subjected to ultraviolet light in the absence of light in the visible portion of the spectrum. The color or appearance imparted to these textiles under ordinary daylight on the stilbene derivatives is not of any great concern, and there has been no proposal to use small amounts of stilbene fluorescent compounds to obtain a whitening effect in ordinary daylight without the use of a substantial amount of a salting out agent.

Another type of stilbene derivative that has been proposed as a fluorescence imparting agent is typified by 4:4 -di-p-aminobenzoyldiaminostilbene-2:2 -disulfonic acid, and other similar derivatives having a terminal NHz group. It has been found, however, that this type of compound, when present on textile fibres, is liable to undergo undesirable changes on contactwith oxidising agents, for instance, bleaching agents of the sodium hypochlorite type, as well as upon exposure to air, especially in the presence of strong sunlight, with the result that the textiles become gradually discolored. Therefore, this agent is not suitable for imparting lasting whiteness to white textile materials, especially if the treated textile is subsequently subjected to a conventional bleaching treatment.

It has been proposed to treat textiles with a stilbene derivative containing at least one triazine nucleus in the molecule in order to impart a whitened appearance to the textile. However, such materials as were obtainable from a commerical supplier showed unsatisfactory stability properties.

It has been found, and quite unexpectedly, that the above discussed disadvantages can be substantially eliminated and an improved whitening effect of greater stability and durability can be obtained by using as a treating agent a derivative of a di-aminobenzoylaminostilbenesulfonic acid formed by the substitution of at least one of the hydrogen atoms in each of the NIH radicals attached to the terminal rings by an organic radical which does not contain an NH: radical directly attached to an aromatic nucleus and which would not itself render the substituted compound formed unstable to light and oxygen. The improved whitening effect and greater stability can be imparted to white textile materials, particularly cotton, linen, and other cellulosic materials.

In the laundering of white articles, sodium hypochlorite and similar bleaching agents are often used in the wash or in the rinse to improve the color of the material or to remove fruit, tea, coffee and similar stains. We have found that the whitening efiect produced when using the specifled stilbene derivatives of the invention is not impaired by such treatment, as contrasted with the detrimental efiect of such treatment on stilbene derivatives used in accordance with the prior art.

The objects achieved in accordance with the mula:

som emn Y Y x1 4 QCH=CHCR rix invention include the provision of a treating process for imparting an improved whitening effect of great stability to textile materials, the provision of white textile materials comprising a where X is alkyl, aryl. aroyl, vacyl, or carbamyl,

small proportion of an aminostilbene derivative adapted to impart an improved whitening eflect of great stability thereto and other objects which will be apparent after the invention is described in more detail hereinafter.

The stilbene derivative may be applied to white textile yarns, fibers, or fabrics before they are made up into articles of clothing, and the like, by treating the textile materials in a dilute aqueous solution of the stilbene derivative at any suitable stage in their manufacture. Alternatively, the stilbene derivative may be applied to articles of clothing, and the like, in connection with domestic or commercial laundering operations; the articles being first washed by customary methods and thereafter immersed or rinsed in a dilute aqueous solution of a stilbene derivative. In laundry practice, it is usual to give the washed product, after the removal of the detergent liquid, several'rinses in clean .water. The stilbene derivative may be applied in either the first or any subsequent rinse.

The accumulation of the substantive whitening agents of the invention 0n the textile material, such as by rinsing after repeated launderjug-treatments, is not harmful. .It is not possible to overblue the textile therewith. In this respect the new agents are distinctly difierent than substantive blue dyes. Under the conditions of use contemplated in this disclosure, any

accumulation of the aminostilbene derivatives 01'- the invention on the textile is harmless, not only from the standpoint of appearance immediately imparted to the textile but also from the standpoint of freedom from potential darkening. The stilbene derivatives of the invention do not darken on exposure to air, sunlight, or bleaching agents, such as sodium hypochlorite. Thus, the treated textile material can be laundered repeatedl in accordance with the invention without harmful efiects.

The above defined stilbene derivatives, for example. may be derived by substituting in a diamlnobenzoylamino-stilbene sulfonic acid, such as 4 4'-di-p-aminobenzoylamino-stilbene-2 ;2'-disulfonic acid, 4:4'-di-p-aminobenzoylamino -stilbene-3:3'-disulfonic acid, 4:4-di-p-aminobenzoylamino-stilbene-2 2','-6 6'-tetrasulfonic acid, one or both amino hydrogen atoms by an organic radical which does not itself contain a terminal NH: radical attached to an aromatic nucleus such and Y is H, alkyl or aryl. In general, the lower aliphatic or aromatic groups are preferred as the X in the above formula. These may be typified by: methyl, ethyl, propyl, isopropyl, butyl, cyclohexyl, phenyl, methylphenyl, dimethylphenyl, benzoyl, methylbenzoyl, dimethylbenzoyl, acetyl, propionyl, butyryl and carbamyl (H2NCO-), methyl carbamyl (HJCNHCO-l,

ethyl carbamyl (H5C2NHCO) and diethyl carbamyl ((HsCz) 2NCO).

vThe stilbene derivatives may contain one or more sulfonic acid groups and these may be attached anywhere in the molecule. The stilbene derivative may be of the symmetrical type or nonsymmetrical type. The benzoyl group may be replaced by a corresponding polynuclear aroyl group. Thus, in the broader aspects of the invention, a (non-primary amino) aroylaminostilbene sulfonic acid is used as the whitening agent. The non-primary amino groups which are directly attached to an aryl group may be secondary (i. e. R,NH), or tertiary (i. e. R2N-), as long as R does not contain a primary amino (NH:) group directly attached to any aryl group.

The above defined stilbene sulfonic acids may be used in the form of their salts (i. e. sodium salt) and it is intended that the term acid" appearing herein include the acid itself and also derivatives such as the salts which contain the anion of the acid. I

The aminostilbene derivative must be water soluble or dispersible in the presence of a detergent and this will exclude groups which impart thereto non-dispersibility in water.

The aminostilbene derivatives used in accordance with the invention should not contain a group or radical which imparts tinctorial properties (i. e. an actual color producing or chromophorous group) or groups which tend to discolor upon exposure to light, air, or bleaching agents such as sodium hypochlorite (i. e. potential color producing or chromophorous groups). For instance, phenolic hydroxy groups would be unsuitable since such phenolic compounds are known to discolor upon exposure to air. Thiophenolic groups are also excluded since they would tend to discolor upon exposure to air. All

' such groups are referred to as color producing groups."

Typical examples of specific aminostilbene derivatives which may be used in accordance with the invention are:

l. 4:4 -di-p benzoylaminobenzoylamino stilbene-2 :2 -disuli'onic acid NH-O o-O-rt-o GO 2. 4:4 -di-p acetylaminobensoylamino stiltions and modifications which come within the bene-zzz -disulfonic acid: scope of the appended claims.

. sour sou:

n cmco-it-O-o NH-OH=CH NH-QO C-O-N-O c-cn. as well as the corresponding meta and ortho com- I. claim: pounds, and salts of the above acid. 1. A process which comprises applying to tex- The proportions in which the said stilbene detile materials an amount in the range from rivatives are to be incorporated in the textile n 0.0001% toabout 0.025%,based on thedryweight materials in order to achieve the objects of the of the textile, or an aminoaroylaminostilbene invention are determined by various factors such sulfonic acid which is free from color producing as the particular stilbene derivative employed and groups and which has the following general forthe nature of the textile material to be treated. As mula:

IH 501E x-E I cir=cn l-x ..-.0 6....

. a general rule, considerably less than 0.05%, in which X is a radical selected from the group based on the dry weight of the textile material, is consisting of aroyl and acyl radicals, and Y is required, and proportions in the range or 0.01% a radical selected from the group consisting of to 0.0001% have been found suitable to produce hydrogen, alkyl and aryl radicals, by treatment the desired effect. Proportions ranging from with an aqueous solution of said acid, said amount 0.0025% to 0.0001% have been found sumcient to of said compound being sufficient to impart a impart an appreciable whitened effect. The whitenin effect to the textile material which amount need not be larger than 0.05%, based on does not discolor upon exposure to light, air and the textile material to achieve a satisfactory bleaching agents. whitening effect. 3n 2. A process which comprises applying to tex- The manner of carrying out the invention in v tile materials an amount in the range from practice and the beneficial results achieved 0.0001% to about 0.025%, based on the dry therefrom willbe apparent from the examples weight of the textile, of a benzoylaminobenzoylgiven below. aminostilbene sulfonic acid which is free from Example 1 color producing groups and primary amino Groups directly attached to an aryl nucleus, by A new white cotton cloth was rinsed for a few treatment with an aqueous solution of said acid, minutes in an aqueous bath containing 0.005% of said amount of said compound being sumcient to the sodium salt of 4:4 -di-p-acetylam1n b nimpart a whitening eflfect to the textile matezoylamino-stilbene l acid; the rial which does not discolor upon exposure to treated cloth after drying and ironing, showed a i t, nand bleaching agents brilliant white appearance. The resulting treat- 3 A process hi comprises applying t t ed cloth contained 0.038% of the stilbene derivat l at l an amount t range from tive, based on the dry weight of the treated'cloth. 0,0001% t 0.01%, based on t dry weight of The treated cloth showed no tendency to discolor th t t of 4, 1. m 1 wh n posed to bright sunlight Over lon P i aminostilbene-2,2'-disulfonic acid which is free not when stored in the dark, or treated with a from colmproducing groups, by treatment with dil te Sodium hy l solution of the an aqueous solution of said'acid, said amount stre h c to r y d in the bleaching o of said compound being sufllcient to impart a textiles. v m whitening effect to the textile material which Emmi, 2 does not discolor upon exposure to light, air and bleaching agents. A mixed batch of towels, tablecloths. piilow- 4. A process which comprises applying to texcases and napkins weighing 7 pounds was washed tile materials an amount in the range from with soap in the usual way, rinsed twice in clean 0.0001% to 0.025%, based on the dry, weight of water, and then given a final rinse in 7 gallons the textile, of an acetylaminobenzoylaminoof water containing 0.005% (calculated upon the stilbene sultonic acid which is free from color water) of the same blue-fluorescent compound as producing groups and primary amino groups used in the above example. The resulting treatdirectly attached to an aryl nucleus, by treated cloth articles contained 0.038% of the stilnn ment with an aqueous solution of said acid, said bene derivative, based on the dry weight of the amount of said compound being sufiicient to imtreated cloth articles. The articles, when dried part a whitening efiect to the textile material and ironed, were all much whiter than those in which does not discolor upon exposure to light, a control test laundered in the same way but air and bleaching agents. without the blue-fluorescent compound, and 5. A process which comprises applying to texthere was no noticeable discoloration or loss of tile materials an amount in the range of whiteness after prolonged exposure to daylight. 0.0001% to 0.01%, based on the dry weight of The foregoing descriptions of specific embodthe textile, of 4,4-di-p-acetylamlnobenzoyliments of the invention are for illustrative puraminostilbene-2,2-disulfonic acid which is free poses only and are not to be construed as lim- 7 from color producing groups by treatment with itations of the invention as it is otherwise disan aqueous solution of said acid, said amount closed and claimed herein. In view of the foreof said compound being suillcient to impart a going disclosure, variations and modifications whitenin eifect to the textile material which thereof will be apparent to one skilled in the does not discolor upon exposure to light, air and art. The invention contemplates all such variableaching agents.

6. A textile material comprising an amount in the range from about 0.0001% to about 0.025% by weight of an aminoaroylaminostilbene sulfonic acid which is free from color producing groups and which has the following general formula:

in which X is a radical selected from the group consisting of aroyl and acyl radicals, and Y is a radical selected from the group consisting of hydrogen, alkyl and aryl radicals, said amount of said compound being sufflcient to impart a whitening eflfect to the textile material which does not discolor upon exposure to light, air and bleaching agents.

7. A textile material comprising an amount in the range from about 0.0001 to about 0.025% by weight of a benzoylaminobenzoylaminostilbene sultonic acid free from color producing groups and primary amino groups directly attached to an aryl nucleus, said amount of said compound being suflicient to impart a whitening effect to the textile material which does not discolor upon exposure to light, air and bleaching agents.

8. A textile material comprising an amount in the range from about 0.0001% to about 0.025% by weight of an acetylaminobenzoylaminostilbene sulfonic acid free from color, producing groups and primary amino groups directly attached to an aryl nucleus, said amount of said compound being suflicient to impart a whitening effect to the textile material which does not discolor upon exposure to light, air and bleaching agents.

8 9. A textile material comprising an amount in the range from about 0.0001% to about 0.025% by weight of 4,4'-di-p-benzoylaminobenzoylaminostiibene-2,2'-disulfonic acid, said amount of said compound being sufficient to impart a whitening REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,089,293 Paine Aug. 10, 1937 2,089,413 Paine Aug. 10, 1937 OTHER REFERENCES -Ser. No. 381,856, Wendt (A. P. 0.), published May 11, 1943. 

1. A PROCESS WHICH COMPRISES APPLYING TO TEXTILE MATERIALS AN AMOUNT IN THE RANGE FROM 0.0001% TO ABOUT 0.025%, BASED ON THE DRY WEIGHT OF THE TEXTILE, OF AN AMINOAROYLAMINOSTILBENE SULFONIC ACID WHICH IS FREE FROM COLOR PRODUCING GROUPS AND WHICH HAS THE FOLLOWING GENERAL FORMULA: 